Adjustable trigger stops for limiting the depression stroke of a trigger for portable tool speed control purposes have been known heretofore. For example, C. J. Frenzel U.S. Pat. No. 3,548,136, dated Dec. 15, 1970, shows several versions of an adjustable trigger stop including a one-intermediate-trigger-position rotary stop in FIGS. 1-4, a two-intermediate-trigger-positions slidable stop in FIGS. 5-6, a two-intermediate-trigger-positions rotary stop in FIGS. 7-8, a one-intermediate-trigger-position pivoted lever stop in FIGS. 9-10, and a one-intermediate-trigger-position rotary stop in FIGS. 11-12, all of these having a rather limited trigger positioning capability, that is, only one or two adjustable positions between no trigger depression and full trigger depression. E. V. Sahrbacker U.S. Pat. No. 3,603,757, dated Sept. 7, 1971, shows an adjustable trigger stop construction wherein the finger-engaging part of the trigger which provides the trigger stop abutting the housing, is secured to and adjusted relative to the slidable part of the trigger by a setscrew having a knob for manual adjustment. While this construction provides a stepless adjustment of the depth of trigger depression, the structure is rather fragile since the external part of the trigger is secured only by the setscrew which could be damaged if the trigger is bumped or the tool dropped. H. W. Brown U.S. Pat. No. 3,761,663, dated Sept. 25, 1973, shows an adjustable trigger stop which also can be adjusted by a rotary knob embedded partially in the face of the trigger. In this version, an eccentric pin on the adjustment shaft raises a stop block to abut the switch frame. This version also has limited trigger positioning capability.
While these prior structures have been useful for their intended purposes, this invention relates to improvements thereover.